ALS is well known, but still a mystery

Between Lou Gehrig's widely-publicized battle with the disease that would soon bear his name, and the terrible, debilitating symptoms associated with it, ALS is an illness that most are familiar with.

But despite its notoriety, it isn't actually that common. In the United States, only about 30,000 people have ALS at any one time, comfortably below the threshold needed to classify it as a rare disease. With this relatively low incidence rate, there hasn't been a lot of money allocated to studying ALS or tracking its prevalence.

Researchers do know a few things about its origins, the most notable being that in about 15 percent of cases, a genetic mutation is present. They also know that war veterans are more likely to contract the disease, though they don't know why.

Beyond that, though, the disease has stayed a mystery for doctors and researchers.

"There are a lot of theories as to why ALS might be more common in veterans and they're all over the place," said Rick Bedlack, associate professor of neurology and director of the Duke ALS Clinic in Durham, N.C.

For Timothy Lowery, who started showing symptoms of ALS after returning from a three-year stint as a contractor in Iraq, the disease did not occur genetically. His family suspects that regular exposure to burn pits — open-air ditches where the military dumped its waste and lit it ablaze — caused him to contract the disease.

Since so little is known about how the disease selects its victims, it may be a long time before their assertions can be proven or disproven.

"I've heard of people that suspect (burn pit exposure) was the reason they got ALS, but the problem with this type of thing is you've got to say 'It's more likely than not' if you're trying to prove causality in a legal sense," said Bedlack. "These are not easy studies to do."

After the Gulf War saw many veterans return home with a variety of symptoms — many of which were often lumped into a blanket diagnosis called "Gulf War syndrome" — researchers started looking for possible causes. One recent study that also may explain some symptoms from those returning from the military's most recent conflicts relates to the microscopic dust particles that are found in the region. The particles, which include tiny fragments of lead, aluminum, fungi, and bacteria, are present in the region's dust at a much higher rate than elsewhere, and some researchers believe they could be the cause of some of the Gulf War syndrome symptoms.

The Department of Defense, however, has said that its own studies do not show the dust to be dangerous.

As for determining a cause of ALS, one place that researchers have flocked is the island of Guam, where for a time, the population saw a rate of the disease that was significantly higher than anywhere else in the world.

There, the native Chamorro people regularly ate the Guam flying foxes that lived on the island, and those foxes regularly ate seeds rich in a toxin found in cyanobacteria — or blue-green algae. Researchers theorized that the flying fox metabolism was biomagnifying that toxin, causing those who consumed them to be at high risk. When the flying foxes went extinct several decades ago, ALS rates dropped significantly, but still stayed at higher-than-average levels, suggesting that the heavy concentrations of cyanobacteria in the region were still contributing to the elevated incidence rates.

Cyanobacteria hotspots have also been discovered in the Persian Gulf, said Bedlack.

"It would be very interesting to see a map of blue-green algae concentrations across that part of the world and to see if that map correlated with the previously described hot spots" of ALS, said Bedlack. "If they could find other hot spots in places the troops have been the past 10-15 years… you'd actually have a hypothesis they could test."

But with little hope of conducting or acquiring reliable research from less-developed regions, such as the Persian Gulf, scientists in the U.S. are pursuing other options.

Several years ago, Massachusetts became the first state to mandate reporting of the disease. The state will release its first findings from its reporting database in the next several months.

And in 2010, the ALS Association established a national registry for those suffering from the disease to report their symptoms. The association is hoping to study trends garnered from the data.

"It's designed to give us a better understanding of what's happening in the country," said Pat Wildman, director of public policy for the ALS Association. "There are a lot of unanswered questions when it comes to this disease."